Similar fiasco when EPA did a showcase project converting DC water supply away from chlorine treatment. Hugely embarrassing and expensive "fix" for a non-problem, that created a much worse problem.

(ETA: It also caused lead to be released- non-lead pipes had actually leached lead from the water over many years, acting as a filter. The lead was chemically bound to both lead and non-lead pipes. Changing the chemistry caused the process to reverse and dump all that lead back into the water at much higher concentrations than would occur just using a 100% lead pipe system.)

And lead paint is similar. In-situ it's pretty harmless. It's the removal that's dangerous and is more likely to poison.

This is why people arguing for "do-something!" actions using "What harm could it do?" reasoning should always be fought until safety is confirmed experimentally the field.

"What harm could it do?" should always be a red flag for "don't know what you don't know" ignorance, and responded to as if it's a real, non-rhetorical question.